# CVE-2026-6721: Multiple Vulnerabilities in IBM Concert Software

> Unauthenticated remote attackers can execute arbitrary OS commands via crafted input in IBM Concert, leading to remote code execution.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** GHSA-v72j-hv4w-mxvh

## What is CVE-2026-6721?

CVE-2026-6721 is a critical command injection vulnerability in Ibm Concert, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

IBM Concert 1.0.0 through 3.0.0 allows an unauthenticated remote attacker can supply specially crafted input that is incorporated into OS commands, resulting in arbitrary command execution on the underlying system. Successful exploitation allows remote code execution with the privileges of the affected application.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-6721?

It affects 1 product.


Products: Ibm Concert.

## How do I fix CVE-2026-6721?

No fix has been published for CVE-2026-6721 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6721 being exploited?

There is no known exploitation of CVE-2026-6721 in the wild and no public exploit code.

## Other vulnerabilities in Ibm Concert

- [CVE-2026-6730](https://insights.sbomify.com/CVE-2026-6730/): Multiple Vulnerabilities in IBM Concert Software (critical 9.8)
- [CVE-2026-6928](https://insights.sbomify.com/CVE-2026-6928/): Multiple Vulnerabilities in IBM Concert Software (critical 9.8)
- [CVE-2026-3627](https://insights.sbomify.com/CVE-2026-3627/): Multiple Vulnerabilities in IBM Concert Software (critical 9.1)
- [CVE-2025-33015](https://insights.sbomify.com/CVE-2025-33015/): Multiple Vulnerabilities in IBM Concert Software (high 8.8)
- [CVE-2026-6794](https://insights.sbomify.com/CVE-2026-6794/): Multiple Vulnerabilities in IBM Concert Software (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6721 and fix it if it is affected.

What it is: CVE-2026-6721 is a critical command injection vulnerability in Ibm Concert, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-6721 in the wild and no public exploit code.

Affected product: Ibm Concert. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-6721/ (Markdown: https://insights.sbomify.com/CVE-2026-6721/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6721
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6721
- OSV: https://osv.dev/vulnerability/CVE-2026-6721

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6721/
Summaries are generated and may contain mistakes; the official description above is the record.